Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
I believe I did.Please post this in the "Amp Guts" thread for posterity.
I haven't read through all 25 pages of this thread but just wanted to say that I assembled an amp using a 1000ASP and a GhentAudio chassis. The ghentaudio.com GK-ASP-MX chassis had all the necessary bits necessary bits making the "build" trivial. At 4.22KG it's not as light as the BP-800 but much lighter than an Ashdown ABM.
I am presently using a ART TubeMP V3 preamp to drive the ASP in turn powering a subway 15 and a Seismic cabinet (Magnum 18LF). While it's ironic that a 12AX7 is ultimately driving switching transistors it works nicely IMO. The voicing selections on the Tube MP are subtle but useful, I like the combined tone with just my Ibanez w/Aguilar pickups plugged into the ART set to electric piano voicing. I might try a Mesa Subway DI box though at 12dBu, I wonder whether the Mesa per-amp XLR out has the moxie to drive the amp to full power.
The ASP seems quite efficient, even with extended periods of E string feedback (about 65Vrms into 4 ohms -- just over 1KW) the chassis was barely warm. In contrast, a PJ BP-800 at less output gets unpleasantly warm to the touch. Getting the full power out of the ICE amp required dialing the ART up quite a lot (the ART is claimed good for 28dBu). I have a power-meter on the power input, so far the biggest number I noticed was about 1200W and of that I'm guessing that the amp is dissipating no more than 200W internally. I was procrastinating on building a 1KW 4 ohm load but I'm motivated now.
I hadn't used an XLR/balanced signal path before for a bass but I like it, very quiet. I'm not too crazy about the binding posts on the chassis but they are quite decent as binding posts go and there is room for a speakon which I will likely add. One missing feature I'd like is a XLR ground lift switch and a mute switch would be nice. The 1000ASP has a number of interesting control features available. There is 12Vdc source that could be used to power a fan, a slim 80mm would probably work fine but I doubt it will be needed.
Overall, I like it. There's nothing like the aroma of hot voice coils in the morning to get the juices flowing
I am presently using a ART TubeMP V3 preamp to drive the ASP in turn powering a subway 15 and a Seismic cabinet (Magnum 18LF). While it's ironic that a 12AX7 is ultimately driving switching transistors it works nicely IMO. The voicing selections on the Tube MP are subtle but useful, I like the combined tone with just my Ibanez w/Aguilar pickups plugged into the ART set to electric piano voicing. I might try a Mesa Subway DI box though at 12dBu, I wonder whether the Mesa per-amp XLR out has the moxie to drive the amp to full power.
The ASP seems quite efficient, even with extended periods of E string feedback (about 65Vrms into 4 ohms -- just over 1KW) the chassis was barely warm. In contrast, a PJ BP-800 at less output gets unpleasantly warm to the touch. Getting the full power out of the ICE amp required dialing the ART up quite a lot (the ART is claimed good for 28dBu). I have a power-meter on the power input, so far the biggest number I noticed was about 1200W and of that I'm guessing that the amp is dissipating no more than 200W internally. I was procrastinating on building a 1KW 4 ohm load but I'm motivated now.
I hadn't used an XLR/balanced signal path before for a bass but I like it, very quiet. I'm not too crazy about the binding posts on the chassis but they are quite decent as binding posts go and there is room for a speakon which I will likely add. One missing feature I'd like is a XLR ground lift switch and a mute switch would be nice. The 1000ASP has a number of interesting control features available. There is 12Vdc source that could be used to power a fan, a slim 80mm would probably work fine but I doubt it will be needed.
Overall, I like it. There's nothing like the aroma of hot voice coils in the morning to get the juices flowing
Attachments
I haven't read through all 25 pages of this thread but just wanted to say that I assembled an amp using a 1000ASP and a GhentAudio chassis. The ghentaudio.com GK-ASP-MX chassis had all the necessary bits necessary bits making the "build" trivial. At 4.22KG it's not as light as the BP-800 but much lighter than an Ashdown ABM.
I am presently using a ART TubeMP V3 preamp to drive the ASP in turn powering a subway 15 and a Seismic cabinet (Magnum 18LF). While it's ironic that a 12AX7 is ultimately driving switching transistors it works nicely IMO. The voicing selections on the Tube MP are subtle but useful, I like the combined tone with just my Ibanez w/Aguilar pickups plugged into the ART set to electric piano voicing. I might try a Mesa Subway DI box though at 12dBu, I wonder whether the Mesa per-amp XLR out has the moxie to drive the amp to full power.
The ASP seems quite efficient, even with extended periods of E string feedback (about 65Vrms into 4 ohms -- just over 1KW) the chassis was barely warm. In contrast, a PJ BP-800 at less output gets unpleasantly warm to the touch. Getting the full power out of the ICE amp required dialing the ART up quite a lot (the ART is claimed good for 28dBu). I have a power-meter on the power input, so far the biggest number I noticed was about 1200W and of that I'm guessing that the amp is dissipating no more than 200W internally. I was procrastinating on building a 1KW 4 ohm load but I'm motivated now.
I hadn't used an XLR/balanced signal path before for a bass but I like it, very quiet. I'm not too crazy about the binding posts on the chassis but they are quite decent as binding posts go and there is room for a speakon which I will likely add. One missing feature I'd like is a XLR ground lift switch and a mute switch would be nice. The 1000ASP has a number of interesting control features available. There is 12Vdc source that could be used to power a fan, a slim 80mm would probably work fine but I doubt it will be needed.
Overall, I like it. There's nothing like the aroma of hot voice coils in the morning to get the juices flowing
So you're connecting your bass to the amp thru a DI (XLR), then connecting the ICE 1000ASP to a cabinet using binding posts? What kind of cables are those? I really prefer Speakon connectors, and would be hesitant using something like this.
Looks cool though, and I am interested in the newer ICE 1000ASP offerings (and above). Hadn't considered a DIY, but looks interesting.
Also, no volume? So volume would need to be controlled by a preamp I guess ...
Thanks,
Ed
Last edited:
There's nothing like the aroma of hot voice coils in the morning to get the juices flowing
I've attached additional photos. The manufacturing attribution is for the chassis kit only (though Ghent does turn-key assemblies). That said, I find the chassis mechanical design admirable (robust, visually appealing and an effective heat sink). As I mentioned, my main design change ask would be for an opening for a speakon rather than binding posts and one for an XLR ground lift switch. Of course I can add those myself but I'd like to not have to.
The binding posts are admittedly a slight PITA to setup, but they are secure when the conductor goes into the barrel and then through the perpendicular hole where it is pinned down by the twist lock. It's solidly connected electrically/mechanically:
I build my own cables using Carol 12AWG two conductor cable with non-solder Neutrik's (PartsExpress) so I just pulled off one of the speakon's on a cable to run into the binding posts. Most cables are likely similar.
You can't really use a standard XLR DI directly (not even in post eq) because DI is intended for FOH mixer use and not at line level. To get 1000W you need a very solid line level, my present means is with an ART mic preamp. It has a level control for input and output:
The voicing knob and the VU meter are entertaining but really, the plain version of the Tube MP is perfectly adequate ($55 Sweetwater) especially if you have adequate eq on the instrument. Crucially, the preamp has both balanced and unbalanced inputs/outputs:
What I'd like to try is to run my bass into a passive DI then via balanced cable into the preamp which would be very noise free.
Both Mesa Subway DI's have in addition to the standard DI level XLR output connector, a higher level preamp XLR output connector that on paper would work directly into the amp. But the Mesa Subway+ DI is literally more expensive than the basic amp module was.
--Ed
"Different strokes for different folks" Muhammed Ali
- Feb 12, 2006
- 61,086
- 5
- 221,205
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
I've got several DIs: a Fishman Pre-EQ Platinum, a Radial Stagebug, an Art Tube MP Studio (not the v3), and a Sonic Farm 2di4 which has line level out. But I hadn't really thought about building an amp. Until now. Maybe down the road I may consider this ...
So I just measured a 93.5Vp swing into a 4 ohm load in response to a 1.25 Vp swing at the XLR (1/2 the delta between +/- input and output point). ICEpower spec's the input impedance at 8k ohms over the audio band. But if either Mesa DI can provide that easily (or more) with the 78dB noise then I'm interested. Thank you for saying.
Incidentally, I do get that the 12dBu spec on the Mesa preamp XLR out means that it should swing 8.72Vpp across 600 ohms (so no problem on an 8K load) but I have to say I am by nature skeptical of such specifications.
The ART TubeMP advertises that it can do 28dBu max on the XLR output but that would be 55Vpp which I submit is wishful thinking. Also the advertised gain for the ICEpower argues that a 90vp swing requires a 4Vp input swing but this is unhelpfully conservative.
I'll try the Mesa DI.
- Feb 12, 2006
- 61,086
- 5
- 221,205
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
There is no such state as overthinking. Spec's are about honest measurement and measurement is how we understand the universe.
I got a Mesa DI (first version). It can indeed drive the amp to full power. But in a flat setting, it requires the master gain to be maxed and the input gain at about 2:30 oclock. I would say that it is breaking a sweat but it's tolerable and it sounds pretty decent with the NS piezo-ish pickups so I'd say it's a contender especially with one box.
I got a Mesa DI (first version). It can indeed drive the amp to full power. But in a flat setting, it requires the master gain to be maxed and the input gain at about 2:30 oclock. I would say that it is breaking a sweat but it's tolerable and it sounds pretty decent with the NS piezo-ish pickups so I'd say it's a contender especially with one box.
Those binding posts are not at "standard" spacing for a dual banana plug, it looks like, right?
- Feb 12, 2006
- 61,086
- 5
- 221,205
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
For some power amps the additional gain from the master is necessary, but there's also plenty of additional clean gain within the input stage as well. The electronics doesn't care, nor do they break a sweat where the controls are positioned, that's why they go all the way up... for the situations where it's needed.
The problem with many of these preamp type devices that can't drive line level is not one of gain but because the internal operating levels are incapable of achieving true line level of +4dBu without distorting. Internally, the electronics operate at about 18 volts.
I did build a load worthy of this amp (and many others). It is 4 ohms and can dissipate 1KW steady state no problemo.
If it does it for a while, the fans need to run. Not as noisy as one might think. But using a load is not about listening so it doesn't matter.
In testing the load my watt-meter showed the input power to the amp was about 1130W with an output of about 1010W (90Vp into the 4 ohms load). The amp is itself dissipating about 120W with a 110Hz sine (A my favorite tone). I let it run for about 5 minutes, the hottest part of the amp appears to be the transformer, it reached 115DF with the lid off but in a small room with a 1KW space heater running (i.e., the load).
I have an Ashdown ABM 300 that does about 150DF at the heatsink (class AB). Gotta like the power efficiency of class D. But if I may be a heretic, I actually, I like the sound of the ICEpower class D amp, it handles the harmonic content of round wound strings well (the strings are what make the tone). Granted it's hard to believe given the hash that comes out of most class D amps. Probably my dogs don't like it, but that's their problem.
--Ed
If it does it for a while, the fans need to run. Not as noisy as one might think. But using a load is not about listening so it doesn't matter.
In testing the load my watt-meter showed the input power to the amp was about 1130W with an output of about 1010W (90Vp into the 4 ohms load). The amp is itself dissipating about 120W with a 110Hz sine (A my favorite tone). I let it run for about 5 minutes, the hottest part of the amp appears to be the transformer, it reached 115DF with the lid off but in a small room with a 1KW space heater running (i.e., the load).
I have an Ashdown ABM 300 that does about 150DF at the heatsink (class AB). Gotta like the power efficiency of class D. But if I may be a heretic, I actually, I like the sound of the ICEpower class D amp, it handles the harmonic content of round wound strings well (the strings are what make the tone). Granted it's hard to believe given the hash that comes out of most class D amps. Probably my dogs don't like it, but that's their problem.
--Ed
That is a valid point and I suppose one reason why a tube preamp could have a high output. I only saw just under 8Vpp at the XLR. If Subway DI runs on 9Vdc it smut have a DC to DC converter. The TubeMP uses 9Vac so only a transformer is needed to step up to the plate voltage needed for the 1947 vintage 12AX7 output device. At least it weighs enough to have a transformer.
Nope, that spacing apparently appeals to some binding post aficionados that want to use gauge-zero speaker wires (which maybe you need if you are driving 6KW into a 0.5 ohm load that is 100 meters distant from the amp).
There is room for a speak-on, I am going to add one (it can be made to look decent too). Ghentaudio has enclosures with speak-on's for Hypex amps but not ICEpower. I think that the majority of their customer base likes binding posts. The case is a standard extrusion, look at the PJ BP-800, it's very similar.
You're describing my stereo system and listening room!
I was thinking in terms of the car audio world where they use many drivers (actually may be less than 1 ohm total impedance) so the current in the system is what matters and IR drops matter. A different form of insanity.You're describing my stereo system and listening room!
That's a nice aluminum case!
It looks targeted for the home hi-fi enthusiast but would make 80% of MI users happy. It would be great if they came up with a case for MI experimenters use chassis where there is room internally for pre-amps, limiter, a fan (if needed) ... and it fits a couple of speakons. Maybe turn the amp module 90-degress to keep from routing input and output wires too close.
